Find Another Planetary System Tonight - Fomalhaut!

Low in the south, a seemingly solitary bright star twinkles in the fall. Although you cannot see it with the unaided eye, the star has a planet in orbit. Find Fomalhaut tonight!

Fomalhaut, imaged in 2009. Image Source

Fomalhaut is the brightest star in Piscis Austrinus, the Southern Fish, and one of the brightest stars in the night sky. In the fall, you can find this star by looking for the brightest star near the southern horizon around 8 PM.

Fomalhaut is the brightest star low in the south in fall evenings. Image: Stellarium and Me

The rest of the stars in Piscis Austrinus are faint and not easy to see low in the sky, or from the city. They represent a single fish, below the constellation Aquarius. The constellation known simply as Pisces is in a different part of the sky, and is drawn as two fish linked by a chain. 

If you find Fomalhaut, you will have also found a planetary system! Fomalhaut is a young star, "only" about 450 million years old, and is surrounded by several debris disks. Just inside the outer disk, a massive planet has been detected. The outer disk has been compared to our Solar System's Kuiper Belt. 

Hubble Space Telescope image showing the planet orbiting Fomalhaut. Image Source

It is exciting to be able to observe a young star system that is in the early stages of forming planets. Perhaps as our telescopes improve through the years, we will be able to track subtle changes in the protoplanetary disk around this star. 

The debris disk imaged in microwave light by ALMA. The blue part of the image is the above Hubble image, the red part shows the star and debris disk glowing in microwave light. Image Source

Fomalhaut is about 25 light years away, which makes it pretty close to Earth in terms of stellar distance. However, even these close stars would be difficult for us to study with robotic spacecraft. A spacecraft traveling as fast as New Horizons would take about 380,000 years to get to this star system. We'll have to keep improving our ground based telescopes, and get working on developing warp drive!




You can always learn the latest news from space at the Dome Planetarium! Follow the us on Facebook or Twitter for daily updates, and come see a show next time you visit the Peoria Riverfront Museum - we teach about space and science everyday.

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